To determine which ones meet this standard, though, we first had to ask what makes a great bike path.

For starters, many on our list are important commuting arteries that give cyclists direct access to business districts while avoiding city traffic and making few street crossings. A few, like Boston's Minuteman Bikeway or Philadelphia's Schuylkill River Trail, were even designed, in part, to bring commuters in from the suburbs where they'd otherwise be out of reach of mass transit.

Rising from the plains to the Rockies and bisecting this mountain town from East to West, the paved, 7.5-mile Boulder Creek Path epitomizes what makes Boulder one of the most active, outdoorsy cities in the country.